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3. FIRST-STAGE REGULATOR
The first-stage regulator is housed and protected within the backpack assembly. It connects to the air cyl-
inder valve using a high pressure hose and a large, easy- to-grip stainless steel hand wheel. The stainless
steel hand wheel provides a positive connection reducing the risk of cross threading or thread damage.
The first stage regulator lowers air cylinder pressure to approximately 115 psi, which is supplied to the
second stage regulator via the intermediate pressure hose. A relief valve activates to protect the system
should the regulator pressure exceed 200 to 225 psi.
A high-pressure connection for the HUD transducer, UAC, and the remote Pressure Gauge/PASS Alarm
on the right shoulder are all housed and protected within the backpack assembly.
4. LOW AIR ALARM
The integrated low air warning alarm emits an audible warbling whistle when the air cylinder pressure
reaches between 1485 psig and 1665 psig. (approximately 33 to 37 percent of the rated capacity of the
air cylinder). The low air warning whistle will operate until the air cylinder pressure drops below 200
psi. The whistle is located in the upper left corner of the backpack and protected by the thermal and im-
pact resistant enclosure.
5. AIR PRESSURE GAUGE / PASS ALARM
A high pressure air hose is routed over the right shoulder strap and attach to the Air Pressure Gauge/PASS
Alarm assembly. The gauge is luminescent for low light viewing and indicates the quantity of air remain-
ing in the air cylinder once the air cylinder valve is opened. Air pressure is illustrated from full "FULL"
to empty "EMPTY" using quarter increments "1/3, 1/2, 3/4 " similar to a fuel gauge on a
vehicle.
Opening the air cylinder valve arms the PASS device as air pressurizes the system. An ascending tone
and alternating green flashing LED lights indicate activation. The PASS device can be manually trig-
gered to full alert by depressing and holding the red alarm button for 1to 2 seconds.
Once the PASS reaches full alert, it can only be reset to normal operation by two slow and deliberate
clicks of the yellow reset button the side of the housing. Reset is indicated by a descending tone. Two
additional slow and deliberate clicks of the yellow reset button will shut-off the PASS device if the air
has been bleed from the system.
Lack of movement will start the staged alarm in approximately 20 seconds. The LED lights will alter-
nate flashing green and red. The alarm will increase in volume approximately every 5 seconds until full
alert at 30 to 35 seconds. In full alert, the LED lights flash red and the alarm tones alternate between
the front mounted speaker.
The PASS device is powered by the 4 C-cell batteries in the backpack. An amber LED in the PASS de-
vice acts as the battery status indicator for the front of the SCBA.
6. THERMALERT
ThermaAlert is a real-time heat alarm, giving an indication of the present state of the temperature, meaning
that it is a sliding curve of heat and time. The ThermaAlart provides an alarm based on the heat and the
time an individual has spent in a fire environment. A firefighter could be in a room at a certain temperature
for 25 miniutes with the Thermalert never going off, or prior to the Thermalert alarm sounding off; or a per-
son could be in a room at a much higher temperature for 5 minutes prior to the alarm going off. It is all de-
pendent on the heat the firefighter is exposed to and the length of time they are exposed. The sound of the
ThermAlert is different from the sound of a standard PASS alarm. It is not a locking alarm; that is,
it activates when the user reaches any point on the curve, but it automatically stops sounding once
the user leaves the range of the curve.
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